Radio wave environment display device and radio wave environment display method

ABSTRACT

A radio wave environment analysis device includes: a processor which acquires radio wave environment data obtained by associating, with position information within an area including a plurality of observation points, an analysis result based on an analysis of the radio wave environment corresponding to a radio wave transmitted from at least one wireless transmitter disposed within the area; and a memory configured to store the radio wave environment data. The processor is configured to select a region that is a part of the area, extract partial radio wave environment data corresponding to the selected part, and output predetermined radio wave environment distribution data based on the extracted partial radio wave environment data on a display device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of PCT International PatentApplication No. PCT/JP2019/009211 filed on Mar. 7, 2019, which claimsthe benefit of priority of Japanese Patent Application No. 2018-044718filed on Mar. 12, 2018, the enter contents of which are incorporatedherein by reference.

FIELD

The present disclosure relates to a radio wave environment displaydevice and a radio wave environment display method.

BACKGROUND

JP-A-2006-352385 discloses a method in which an area to be estimated isdivided into minute sections, and reception quality from a plurality ofinstalled base stations is grasped in each minute section.JP-A-2006-352385 discloses a method of estimating an area in which ahandover occurs by detecting a handover condition with reference to adifference between the reception quality of a minute section and thereception quality of another minute section adjacent to the minutesection.

SUMMARY

The present disclosure has been made in view of the related-artcircumstances described above, and an object thereof is to provide aradio wave environment display device and a radio wave environmentdisplay method that assist in efficiently extracting and visualizing ananalysis result on a region or a flow line desired to be observed by auser when a radio wave environment analysis performed for a wide area isdisplayed.

The present disclosure provides a radio wave environment display deviceincluding: a processor configured to acquire radio wave environment dataobtained by associating, with position information within an areaincluding a plurality of observation points, an analysis result based onan analysis of a radio wave environment corresponding to a radio wavetransmitted from at least one wireless transmitter arranged within thearea; and a memory configured to store the radio wave environment data,wherein the processor is configured to select a region that is a part ofthe area, extract partial radio wave environment data corresponding tothe selected part, and output predetermined radio wave environmentdistribution data based on the extracted partial radio wave environmentdata on a display device.

The present disclosure provides a radio wave environment display methodto be performed in a radio wave environment display device, the radiowave environment display method including: acquiring radio waveenvironment data obtained by associating, with position informationwithin an area including a plurality of observation points, an analysisresult based on an analysis of a radio wave environment corresponding toa radio wave transmitted from at least one wireless transmitter arrangedwithin the area; storing the radio wave environment data into a memory;selecting a region that is a part of the area, and extracting partialradio wave environment data corresponding to the selected part; andoutputting predetermined radio wave environment distribution data basedon the extracted partial radio wave environment data on a displaydevice.

According to the present disclosure, an analysis result on a region or aflow line desired to be observed by a user can be efficiently extractedand visualized when the radio wave environment analysis performed forthe wide area is displayed.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram illustrating an example of a hardwareconfiguration of a radio wave environment display device according toEmbodiment 1.

FIG. 2 is a diagram illustrating an example of a model area simulated bythe radio wave environment display device according to Embodiment 1.

FIG. 3 is a flowchart illustrating a first example of an operationprocedure of a radio wave environment analysis at a point in the modelarea shown in FIG. 2.

FIG. 4 is a diagram illustrating an example of a model area simulated bythe radio wave environment display device according to Embodiment 1.

FIG. 5 is a flowchart illustrating a second example of the operationprocedure of the radio wave environment analysis at the point in themodel area shown in FIG. 2.

FIG. 6 is a diagram illustrating an example of a model area simulated bythe radio wave environment display device according to Embodiment 1.

FIG. 7 is a flowchart illustrating a modification of the second exampleof the operation procedure of the radio wave environment analysis at thepoint in the model area shown in FIG. 2.

FIG. 8 is a diagram illustrating an example of a model area simulated bythe radio wave environment display device according to Embodiment 1.

FIG. 9 is a diagram schematically illustrating an example of calculationof a radio wave attenuation amount of radio waves at a point locatedwithin a range of 1° in which radio waves are transmitted from atransmission point D0.

FIG. 10 is a flowchart illustrating a third example of the operationprocedure of the radio wave environment analysis at the point in themodel area shown in FIG. 2.

FIG. 11 is a diagram illustrating an example of a visualization resultof a radio wave environment targeted in a shopping mall in which aplurality of access points are arranged and an example of an extractionrange designated by a user in a radio wave environment display deviceaccording to Embodiment 2.

FIG. 12 is a diagram illustrating an example of a visualization resultof a radio wave environment targeted in a shopping mall in which aplurality of access points are arranged and an example of a flow linedesignated by a user in the radio wave environment display deviceaccording to Embodiment 2.

FIG. 13 is a diagram illustrating respective coverage areas of theplurality of access points arranged in the shopping mall shown in FIG.11 and an example of a flow line designated by a user.

FIG. 14 is a graph illustrating a transition example of the number ofterminal connections or throughput at each of the access points on theflow line shown in FIG. 13.

FIG. 15 is a diagram illustrating respective coverage areas of theplurality of access points arranged in the shopping mall shown in FIG.11 and an example of an extraction range designated by a user.

FIG. 16 is a graph illustrating a transition example of the number ofterminal connections or throughput at each of the access points in theextraction range shown in FIG. 15.

FIG. 17 is a diagram illustrating an example of a visualization resultof a radio wave environment shown for each height from a floor surfacein a radio wave environment display device according to a modificationof Embodiment 2.

FIG. 18 is a diagram schematically illustrating an example of anoperation of visualizing the radio wave environment for each height.

DETAILED DESCRIPTION Background of Contents of Embodiment 1

An example of a ray tracing method is described in Tetsuro IMAI, “MobileRadio Propagation Simulation Based on Ray-Tracing Method”, IEICETransactions on Communications, Vol. J92-B, No. 9, pp. 1333-1347,September 2009 (hereinafter referred to as “IMAI”). In the ray tracingmethod, radio wave propagation characteristics can be simulated bygeometrically tracing a ray (that is, a radio wave line as an example ofa ray) from a transmission point to a reception point. However, in orderto obtain a highly accurate result in the ray tracing method, data (forexample, electrical characteristics) of a scattering body (structure)including a shape and a material is required. Since rays that have manyinteractions such as reflection, diffraction, and transmission aretraced for many scattering bodies over a wide range, a large amount oftime is required for simulation calculation (in other words, an analysisof a radio wave environment corresponding to transmission of radio wavesfrom the transmission point). In particular, when a wide area (forexample, a large facility such as a shopping mall or a wide areaoutdoors) is targeted, a huge amount of simulation calculation isrequired and it takes time to analyze the radio wave environment even byusing the technique described in IMAI or JP-A-2006-352385, which is oneof the disadvantages during radio wave environment visualizationgenerated based on the analysis.

Embodiment 1

Therefore, in the following Embodiment 1, an example of a radio waveenvironment display device and a radio wave environment display methodthat assist in efficiently analyzing a radio wave environment for a widearea and visualizing the radio wave environment at a higher speed willbe described.

Hereinafter, respective embodiments specifically disclosing the radiowave environment display device and the radio wave environment displaymethod according to the present disclosure will be described in detailwith reference to the drawings as appropriate. However, unnecessarilydetailed description may be omitted. For example, detailed descriptionof a well-known matter or repeated description of substantially the sameconfiguration may be omitted. This is to avoid unnecessary redundancy inthe following description and to facilitate understanding of a personskilled in the art. The attached diagrams and the following descriptionare provided in order for a person skilled in the art to sufficientlyunderstand the present disclosure, and are not intended to limit thematters described in the scope of the claims.

In the following embodiments, a plurality of observation points (inother words, reception points) and at least one wireless transmitter (inother words, transmission point) are provided in a target area(hereinafter abbreviated as “area”) for visualization of a radio waveenvironment, and as the area, a wide area such as outdoors will bedescribed as an example. In the following description, a radio waveenvironment refers to reception quality at a point in an area calculatedin an analysis (simulation) performed by the radio wave environmentdisplay device when radio waves are transmitted (radiated) from awireless transmitter arranged in a transmission point (with reference tobelow). The reception quality includes, for example, reception power (inother words, reception electric field strength) and an arrivaldirection.

FIG. 1 is a block diagram illustrating an example of a hardwareconfiguration of a radio wave environment display device 100 accordingto Embodiment 1. The radio wave environment display device 100 as anexample of a radio wave environment analysis device uses analysis basicdata 7 b related to an area in which a transmission point (for example,the wireless transmitter) is arranged to analyzed a radio waveenvironment (in other words, simulate a radio wave environment in a casewhere radio waves transmitted from a transmission point is received atrespective points in the area) (with reference to FIGS. 3, 5, 7, and10). The radio wave environment display device 100 displays analysisresult data (for example, a reception power distribution diagramindicating what kind of reception power the radio waves transmitted fromthe transmission point are received at respective points in the area) ofthe analysis.

The radio wave environment display device 100 includes a processor 1, aROM 2, a RAM 3, a keyboard 4, a mouse 5, a display 6, and a Hard DiskDrive (HDD) 7. The ROM 2, the RAM 3, the keyboard 4, the mouse 5, thedisplay 6, and the HDD 7 are connected to the processor 1 via aninternal bus or the like in a way that data or information can be inputand output.

The processor 1 is configured with, for example, a Central ProcessingUnit (CPU), a Micro Processing Unit (MPU), a Digital Signal Processor(DSP), or a Field Programmable Gate Array (FPGA). The processor 1functions as a control unit of the radio wave environment display device100, controls overall operations of respective units of the radio waveenvironment display device 100, inputs and outputs data or informationinto and from respective units of the radio wave environment displaydevice 100, calculates data, and stores data or information. Theprocessor 1 operates according to a program 7 a stored in the HDD 7. Theprocessor 1 acquires current time information by using the ROM 2 and theRAM 3 at the time of performing the processing, and outputs analysisresult data 7 c generated by various kinds of analyses to be describedlater to the display 6 and displays the analysis result data 7 c.

The ROM 2 is a read-only memory, and stores a program and data of anOperating System (OS) in advance. The OS program is executed along withstartup of the radio wave environment display device 100.

The RAM 3 is a writable and readable memory, is used as a work memory atthe time of executing various kinds of radio wave environment analyses(with reference to FIGS. 3, 5, 7, and 10), and temporarily stores dataor information to be used or generated during the various kinds of radiowave environment analyses.

The keyboard 4 and the mouse 5 as examples of an operation input unithas a function as human interfaces with a user, and a user operation isinput thereby. In other words, the keyboard 4 and the mouse 5 are usedfor various settings in various processing executed by the radio waveenvironment display device 100.

The display 6 as an example of a display device is configured with, forexample, a display device such as a Liquid Crystal Display (LCD) or anorganic Electroluminescence (EL). The display 6 has a function as ahuman interface with a user, and displays display data 7 d correspondingto contents of various settings or an operating state of the radio waveenvironment display device 100, various calculation results and ananalysis result.

The HDD 7 stores the program 7 a for executing various radio waveenvironment analyses (with reference to FIGS. 3, 5, 7, and 10), theanalysis basic data 7 b to be used in the various radio wave environmentanalyses, the analysis result data 7 c corresponding to an analysisresult based on the various radio wave environment analyses, and thedisplay data 7 d generated based on the analysis result data 7 c. Theanalysis basic data 7 b includes, for example, data of a map or layoutin the area, scattering body data in which a type (for example, amaterial) of a scattering body (that is, an obstacle that blocksprogress of the radio waves) in the area are associated with a materialconstant (for example, a radio wave attenuation amount) corresponding tothe type, and various data or information such as an arrangementposition of the wireless transmitter in the area (with reference tobelow).

The program for analyzing the radio wave environment in the area is readfrom the HDD 7 to the RAM 3 via the processor 1 and executed by theprocessor 1. The program may be recorded in a recording medium (notshown, for example, a CD-ROM) other than the HDD 7, and may be read intothe RAM 3 by a corresponding reading device (not shown, for example, aCD-ROM drive device).

As described above, the analysis basic data 7 b to be used in the radiowave environment analysis in the area includes, for example, thefollowing data or information: (1) data such as transmission power(dBm), a frequency, and a modulation method of a signal transmitted froma wireless transmitter arranged in the area (for example, a wirelesstransmitter arranged at a transmission point BO in FIG. 4, and accesspoints P1, AP2, AP3, AP4, AP5 shown in FIG. 11), a gain and a height ofan arrangement position of an antenna, etc., (2) data such as a gain anda height of an arrangement position of an antenna in a wireless receiverassumed at the point (that is, a virtual reception point) in the area,(3) data related to two-dimensional or three-dimensional size of thearea, (4) data related to a three-dimensional size and position (thatis, two-dimensional coordinates within the area) of a scattering body(that is, an obstacle that blocks the progress of the radio waves), and(5) data of a setting value of a lower limit value (for example, “−100dBm”) of reception quality (for example, reception power) calculatedbased on the analysis.

The radio wave environment display device 100 according to Embodiment 1can calculate, based on the analysis basic data 7 b, the reception powerand arrival directions of radio waves at respective points in the area(for example, a plurality of points distributed in an area of 100*100 orthe like), by using, for example, a known ray tracing method (withreference to, for example, IMAI) or a known statistical estimationmethod. Therefore, in Embodiment 1, details of the method of calculatingthe reception power of the radio waves at the point in the area will beomitted.

First Example of Analysis

FIG. 2 is a diagram illustrating an example of a model area simulated bythe radio wave environment display device 100 according to Embodiment 1.As shown in FIG. 2, a first example of the model area simulated by theradio wave environment display device 100 according to Embodiment 1 is awide area, for example, outdoors. As an example of the model area, FIG.2 shows a map MP1 of an area having an area of 5 km*5 km (*: an operatorindicating multiplication)=25 km². Data of the map MP 1 is included inthe analysis basic data 7 b. Positions P1, P2, P3 indicate observationpoints (in other words, radio wave reception points or measurementpoints) that are targets of simulation of the radio wave environment ina case where radio waves (that is, radio signals for simulation) aretransmitted from a transmission point (not shown) arranged in the areaof the map MP1 shown in FIG. 2.

FIG. 3 is a flowchart illustrating a first example of an operationprocedure of a radio wave environment analysis at the point in the modelarea shown in FIG. 2. The operation procedure shown in FIG. 3 isexecuted by, for example, the processor 1 of the radio wave environmentdisplay device 100. In the first example of the analysis, since theanalysis based on the radio wave environment display device 100 isperformed at a higher speed, a volume of a scattering body (for example,a building) that blocks progress of the radio waves transmitted from atransmission point arranged in the map MP1 (area) shown in FIG. 2 islimited to a predetermined value (including a volume initial value to bedescribed later) or more, a scattering body having a volume less thanthe predetermined value is determined not to exist in the analysis.

In FIG. 3, various parameters are initialized on the radio waveenvironment display device 100 by a user operation (S1). Specifically,as the various parameters, a volume initial value of the scattering body(for example, 100 m³ or more), a volume reduction value for increasingthe number of scattering bodies to be referred to in the analysis (forexample, 10 m³), observation points (for example, the positions P1, P2and P3), and an observation point error setting value (for example, 3dB) as an example of a convergence condition for terminating theanalysis are set.

The radio wave environment display device 100 uses the parameter of thevolume initial value of the scattering body set in step S1 and theanalysis basic data 7 b to perform a first analysis of a radio waveenvironment at a point in the area in which a scattering body having avolume of a volume initial value (for example, 100 m³ or more) (S2) isassumed to be used. That is, the radio wave environment display device100 calculates, for each point, reception quality (for example,reception power and arrival direction) of radio waves from the wirelesstransmitter (not shown) arranged at the transmission point located onthe map MP1 based on the analysis basic data 7 b, and stores calculationresults of the reception power and the arrival direction at eachposition (location) on the map MP1 in the HDD 7 as the analysis resultdata 7 c.

After step S2, the radio wave environment display device 100 performs asetting of increasing the number of scattering bodies arranged in themap MP1 (area) based on the volume reduction value for increasing thenumber of scattering bodies that is set in step S1 (S3). Specifically,the radio wave environment display device 100 sets use of a scatteringbody having a volume of a volume initial value (for example, 100 m³ ormore) as a volume of a scattering body to be referred to in the firstanalysis. The radio wave environment display device 100 sets use of ascattering body having a volume of a value obtained by subtracting (inother words, decreasing) the volume reduction value once from the volumeinitial value (for example, 90 m³ or more=100 m³ or more−10 m³) as avolume of a scattering body to be referred to in a second analysis.Thus, the radio wave environment display device 100 can perform theanalysis by increasing the number of scattering bodies to be referred toin the second analysis from the number of scattering bodies to bereferred to in the first analysis.

After step S3, the radio wave environment display device 100 uses thevolume value of the scattering body set in step S3 and the analysisbasic data 7 b to perform the second analysis of the radio waveenvironment at the point in the area in which the use of the scatteringbody having a volume of the volume value (=for example, 90 m³ or more)(S4). That is, the radio wave environment display device 100 calculates,for each point, reception quality (for example, reception power andarrival direction) of the radio waves from the wireless transmitter (notshown) arranged at the transmission point located on the map MP1 basedon the analysis basic data 7 b, and stores calculation results of thereception power and the arrival direction at each position (location) onthe map MP1 in the HDD 7 as the analysis result data 7 c.

The radio wave environment display device 100 calculates, for each ofthe observation points on the map MP1 (that is, all the positions P1,P2, P3 set in step S1), an error (that is, a difference) between theanalysis result data 7 c obtained by the current analysis and theanalysis result data 7 c obtained by an immediately preceding analysisand compares these errors (S5).

As a result of the comparison in step S5, the radio wave environmentdisplay device 100 determines whether or not the analysis result data 7c has converged (that is, a difference calculated in step S5 is equal toor less than the error setting value set in step S1) at the respectiveobservation points (S6) (that is, all positions P1, P2, P3 set in stepS1).

If it is determined that the analysis result data 7 c has not convergedat the respective observation points (that is, all the positions P1, P2,P3 set in step S1) (S6, NO), the processing of the radio waveenvironment display device 100 returns to step S3. That is, the radiowave environment display device 100 performs a setting of increasing thenumber of scattering bodies arranged in the map MP1 (area) based on thevolume reduction value for increasing the scattering bodies that is setin step S1 (S3). Accordingly, the radio wave environment display device100 repeats a series of processing of steps S3, S4, S5, and S6 until itis determined that the analysis result data 7 c has converged atrespective observation points (that is, all positions P1, P2, P3 set instep S1).

If it is determined that the analysis result data 7 c has converged atrespective observation points (that is, all the positions P1, P2, and P3set in step S1) (S6, YES), the radio wave environment display device 100terminates the radio wave environment analysis at the point in the area.Further, the radio wave environment display device 100 displays, on thedisplay 6, an analysis result (not shown) of the radio wave environmentanalysis at the point in the area (S7).

As described above, the radio wave environment display device 100according to Embodiment 1 analyzes a radio wave environmentcorresponding to transmission of a radio wave from a wirelesstransmitter arranged in an area having a plurality of observation points(for example, positions P1, P2, P3). The radio wave environment displaydevice 100 analyzes, in the processor 1, a radio wave environment usinga scattering body having a volume equal to or more than an initial value(for example, a volume initial value), and stores the analysis resultdata 7 c of the radio wave environment at each of the plurality ofobservation points based on the analysis in the HDD 7 (an example of amemory). The radio wave environment display device 100 analyzes theradio wave environment using a scattering body whose volume is reducedby a volume reduction value (an example of a first predetermined value,for example, 10 m³). The radio wave environment display device 100terminates the radio wave environment analysis if a difference of theanalysis result data 7 c of the radio wave environment in each of theplurality of observation points based on the analysis using a scatteringbody before volume reduction of the volume reduction value and theanalysis result data 7 c of the radio wave environment in each of theplurality of observation points based on the analysis using a scatteringbody after volume reduction of the volume reduction value is equal to orless than the error setting value (an example of a second predeterminedvalue, for example, 3 dB).

Accordingly, since the radio wave environment display device 100 canefficiently perform a radio wave environment analysis for a wide areasuch as outdoors (for example, an area of 25 km² shown in the map MP1),the radio wave environment display device 100 can assist in visualizingthe radio wave environment at a higher speed. That is, as describedabove, in the radio wave environment analysis, a volume of thescattering body that blocks the progress of the radio waves is limitedto the volume initial value and a volume value reduced by the volumereduction value, so that scattering bodies having a volume value lessthan the initial volume value and the volume value reduced by the volumereduction value are excluded. Therefore, the radio wave environmentdisplay device 100 can perform the analysis at a speed higher than ananalysis of the radio wave environment at each point for all thescattering bodies actually arranged on the map MP1.

Further, even if the analysis is performed with the volume of thescattering body being reduced by the volume reduction value, theanalysis is terminated when only a difference less than the errorsetting value is obtained at respective observation points (that is, allobservation points), so that the radio wave environment display device100 can acquire the analysis result data 7 c with high accuracy whileperforming the analysis at a higher speed. For example, in obtaining ofthe analysis results of the radio wave environment over the entire area,there is a need that the observation points (for example, positions P1,P2, P3) are arranged at a plurality of points desired to be observed bya user, and the radio wave environment at points other than thoseobservation points are desired to be roughly grasped through analysis(that is, simulation). In this case, the analysis is performed at ahigher speed and the analysis result data 7 c with high accuracy canalso be acquired, so that the radio wave environment display device 100can also generate the analysis result data 7 c of the radio waveenvironment that accurately satisfies the need of the user. In otherwords, the radio wave environment display device 100 can acquire theanalysis result data 7 c with high accuracy while performing theanalysis at a higher speed even if there are interactions such asreflection, transmission, and diffraction of radio waves that exceed apredetermined number of times (for example, 4 to 5 times), which ispointed out as a limit when the ray tracing method is used in a widearea such as outdoors.

Second Example of Analysis

FIG. 4 is a diagram illustrating an example of a model area simulated bythe radio wave environment display device 100 according to Embodiment 1.The same elements as those in the first example of the analysis aredenoted by the same reference numerals, the description thereof will besimplified or omitted, and different contents will be described. Asshown in FIG. 4, a second example of the model area simulated by theradio wave environment display device 100 according to Embodiment 1(that is, a second example of the radio wave environment analysis at thepoint in an area) is a wide area, for example, outdoors or the like.FIG. 4 shows, as an example of the model area, a plurality of blockareas obtained by dividing the map MP1 (with reference to FIG. 2) of anarea having an area of 5 km*5 km (*: an operator indicatingmultiplication)=25 km² or more. An area of each block area(specifically, a first block area DST1, block areas DSTw1, DSTs2, DSTs3. . . ) is 1 km*1 km=1 km², for example.

Unlike the first example of the radio wave environment analysis, in thesecond example of the radio wave environment analysis, the radio waveenvironment display device 100 divides an entire area of the map MP1shown in FIG. 4 into a plurality of block areas and sets each block areaas an analysis target without targeting the entire area of the map MP1.For example, in the second example of the radio wave environmentanalysis, it is assumed that the transmission point BO is arranged inthe first block area DST1 generated on the map MP1, a radio wave ofpredetermined strength (for example, 0 dBm) is transmitted, and a radiowave environment is analyzed for the first block area DST1. Further, itis assumed that a virtual secondary transmission point (that is, asecondary wireless transmitter) that transmits radio waves having thesame strength as the above-mentioned predetermined strength is arrangedin any of adjacent boundary positions of each block area (for example, amidpoint position of one side in a longitudinal direction of a blockarea (for example, positions Bs1, Bs2) and a midpoint position of oneside orthogonal to the one side in the longitudinal direction (forexample, a position Bw1)), and the radio wave environment analysis isperformed for the remaining block areas other than the first block areaDST1. Lastly, in consideration of a lower limit of the reception qualityof the radio wave environment and the analysis result data 7 c in thefirst block area DST1, strength of the radio wave transmitted by thesecondary wireless transmitter arranged at each of the secondarytransmission points is corrected, and thus the radio wave environment atthe point within the entire area is analyzed (with reference to FIG. 5).

FIG. 5 is a flowchart illustrating a second example of an operationprocedure of a radio wave environment analysis at a point in the modelarea shown in FIG. 2. The operation procedure shown in FIG. 5 isexecuted by, for example, the processor 1 of the radio wave environmentdisplay device 100. In the second example of the analysis, in order tospeed up the analysis of the radio wave environment display device 100,the map MP1 (area) shown in FIG. 4 is divided into a plurality of blockareas, each block area is analyzed, and when an analysis result of eachblock area is used to generate an analysis result in the entire area,the analysis result of each block area is corrected.

In FIG. 5, various parameters are initialized on the radio waveenvironment display device 100 by a user operation (S11). Specifically,as the various parameters, the radio wave environment display device 100divides an area to be analyzed (for example, an area of the map MP1)into a plurality of block areas so as to reduce the number of scatteringbodies arranged at each point of the map MP1 (area) to be equal to orless than a predetermined value. Alternatively, the radio waveenvironment display device 100 divides the same area (refer to theabove) into a plurality of blocks by a user operation. Further, avirtual secondary transmission point (for example, a position Bs1) isset at a predetermined position (for example, a midpoint position) of aboundary between a block area (for example, the first block area DST1)and another block area (for example, the block area DSTs2) which areadjacent each other.

The radio wave environment display device 100 uses the analysis basicdata 7 b to analyze, for the first block area DST1 (with reference toFIG. 4) among the plurality of block areas set in step S11, the radiowave environment at each point in which the scattering body arranged inthe first block area DST1 is assumed to be used (S12). That is, theradio wave environment display device 100 calculates, for each point inthe first block area DST1, reception quality (for example, receptionpower and arrival direction) of radio waves from the wirelesstransmitter (not shown) arranged at the transmission point BO located onthe map MP1 based on the analysis basic data 7 b, and stores calculationresults of the reception power and the arrival direction at each pointinto the HDD 7 as the analysis result data 7 c.

The radio wave environment display device 100 uses the analysis basicdata 7 b to analyze, for a block area (for example, block areas DSTs2,DSTw1) adjacent to the first block area DST1, the radio wave environmentat each point, in which a case is assumed where radio waves ofpredetermined strength are transmitted from the virtual secondarytransmission point (for example, the position Bs1) set in step S11(S13). The predetermined strength is, for example, the same strength asthe strength (0 dBm) of the radio wave transmitted from the transmissionpoint BO. Further, the radio wave environment display device 100determines whether or not the similar radio wave environment analysis isperformed for the block areas provided in the entire area of the map MP1(S14). The radio wave environment display device 100 repeats theprocessing of step S13 until the similar radio wave environment analysisis performed for the block areas provided in the entire area of the mapMP1 (S13, NO).

On the other hand, if it is determined that the similar radio waveenvironment analysis is performed for the block areas provided in theentire area of the map MP (S14, YES), the radio wave environment displaydevice 100 synthesizes the analysis result data 7 c of the analyses forthe respective block areas to generate the analysis result data 7 c forthe entire area in the map MP1 (S15).

After step S15, the radio wave environment display device 100 correctsthe analysis result data 7 c of the analyses for the respective blockareas based on the analysis result data 7 c (an analysis result)corresponding to the first block area DST1 (S16).

Here, correction of the analysis result data 7 c in each of the blockareas DSTs2 adjacent to the first block area DST1 and the block areaDSTs3 adjacent to the block area DSTs2 will be briefly described.

First, it is assumed that the strength of the radio wave transmittedfrom the transmission point BO is “0 dBm”, and reception power(strength) of the radio wave at the boundary position (for example, theposition Bs1) in the analysis result data 7 c corresponding to the firstblock area DST1 in step S13 is “−40 dBm”. As described above, thestrength of the radio wave transmitted from the secondary wirelesstransmitter (not shown) assumed to be arranged at the position Bs1 ofthe secondary transmission point in the block area DSTs2 is uniformlyset to “0 dBm”. Accordingly, in step S16, the analysis result data 7 ccorresponding to the block area DSTs2 is corrected so as to be uniformlyadded by about “−40 dBm” from the analysis result data 7 c at respectivepoints in the block area DSTs2 calculated in step S13.

Next, it is assumed that the reception power (strength) of the radiowave at the boundary position (for example, the position Bs2) in theanalysis result data 7 c corresponding to the block area DSTs2 in stepS13 is “−25 dBm”. As described above, the strength of the radio wavetransmitted from the secondary wireless transmitter (not shown) assumedto be arranged at the position Bs2 of the secondary transmission pointin the block area DSTs3 is uniformly set to “0 dBm”. Accordingly, instep S16, the analysis result data 7 c corresponding to the block areaDSTs3 is corrected so as to be uniformly added by about “−65 dBm” (=“−40dBm” which is the correction amount of the first block area DST1+“−25dBm” which is the correction amount of the block area DSTs2) from theanalysis result data 7 c at respective points in the block area DSTs2calculated in step S13.

In step S16, the radio wave environment display device 100 corrects theanalysis result data 7 c so as not to fall below the lower limit value(for example, −100 dBm) of the reception quality (for example, receptionpower) included in the analysis result data 7 c based on the radio waveenvironment analysis. For this reason, when the reception quality aftercorrection (for example, reception power) is equal to or less than thelower limit in the correction of step S16, the radio wave environmentdisplay device 100 calculates the analysis result data 7 c employing thelower limit value as the reception quality (for example, receptionpower) at that point.

After step S16, the radio wave environment display device 100 terminatesthe radio wave environment analysis at the point in the area of the mapMP1. Further, the radio wave environment display device 100 displays, onthe display 6, an analysis result (not shown) of the radio waveenvironment analysis at the point in the area of the map MP1 (S17).

As described above, the radio wave environment display device 100according to Embodiment 1 analyzes a radio wave environmentcorresponding to transmission of radio waves of predetermined strength(for example, 0 dBm) from a wireless transmitter (not shown) arranged inan area (for example, the transmission point BO) of the map MP1. Theradio wave environment display device 100 divides the area into aplurality of block areas, analyzes, in the processor 1, a radio waveenvironment by using a scattering body located in the first block areaDST1 in which the wireless transmitter is arranged, and stores, into theHDD 7 (an example of a memory), the analysis result of the radio waveenvironment at each point of the first block area DST1 based on theanalysis. The radio wave environment display device 100 virtuallyarranges a secondary wireless transmitter that transmits radio waves ofpredetermined strength (for example, 0 dBm) at a boundary position whereblock areas including the first block area DST1 are adjacent, andanalyzes the radio wave environment corresponding to the radio wavetransmission from the secondary radio transmitter for each block areaother than the first block area DST1 (for example, block areas DSTw1,DSTs2, DSTs3, . . . ). Based on the analysis result of the radio waveenvironment in the first block area DST1, the radio wave environmentdisplay device 100 corrects the analysis of the radio wave environmentcorresponding to the transmission of radio waves from the secondarywireless transmitter which is performed for each block area other thanthe first block area DST1.

Therefore, a wide area such as outdoors (for example, an area of 25 km²or more shown in the map MP1) can be divided into a plurality of blockareas and the radio wave environment can be efficiently analyzed foreach block area, so that the radio wave environment display device 100can visualize the radio wave environment at a higher speed. In addition,since the reliability of the analysis result based on the analysis(simulation) for each block area can be improved by finely dividing andanalyzing the block area to be analyzed, the radio wave environmentdisplay device 100 can accurately guarantee the generation accuracy ofthe analysis result data for the entire area after the correction.Therefore, the radio wave environment display device 100 can perform theanalysis at a speed higher than an analysis of the radio waveenvironment at each point for all the scattering bodies actuallyarranged on the map MP1.

For example, in obtaining of the analysis results of the radio waveenvironment over the entire area, there is a need that the observationpoints are arranged at a plurality of points desired to be observed by auser, and the radio wave environment at points other than thoseobservation points are desired to be roughly grasped through analysis(that is, simulation). In this case, since each of the plurality ofblock areas is analyzed at a higher speed and the synthesized analysisresult for each block area is also corrected, the analysis result data 7c with high accuracy can also be acquired, so that the radio waveenvironment display device 100 can also generate the analysis resultdata 7 c of the radio wave environment that accurately satisfies theneed of the user. In other words, the radio wave environment displaydevice 100 can acquire the analysis result data 7 c with high accuracywhile performing the analysis at a higher speed even if there areinteractions such as reflection, transmission, and diffraction of radiowaves that exceed a predetermined number of times (for example, 4 to 5times), which is pointed out as a limit when the ray tracing method isused in a wide area such as outdoors.

The radio wave environment display device 100 may individually performthe same analysis (with reference to FIG. 3) as the analysis describedin the first example of the analysis in the analysis for each block areain steps S12 and S13. Accordingly, the radio wave environment displaydevice 100 can perform analysis in consideration of the magnitude of thevolume of the scattering body arranged for each block area, andtherefore, the analysis can be performed at a higher speed.

Modification of Second Example of Analysis

FIG. 6 is a diagram illustrating an example of a model area simulated bythe radio wave environment display device 100 according to Embodiment 1.The same elements as those in the first example or second example of theanalysis are denoted by the same reference numerals, the descriptionthereof will be simplified or omitted, and different contents will bedescribed. As shown in FIG. 6, a modification of the second example ofthe model area simulated by the radio wave environment display device100 according to Embodiment 1 (that is, the second example of the radiowave environment analysis at the point in an area) is similarly a widearea, for example, outdoors or the like. As an example of the modelarea, FIG. 6 shows the map MP1 (with reference to FIG. 2) of an areahaving an area of 5 km*5 km (*: an operator indicatingmultiplication)=25 km².

Unlike the second example of the radio wave environment analysis, in themodification of the second example of the radio wave environmentanalysis, the radio wave environment display device 100 arranges thewireless transmitter at a predetermined position (for example, aposition of the transmission point C0) of the map MP1, and sets acircular area having a radius r1 (a predetermined value) or less fromthe transmission point C0 as a first block area DSTc1 without targetingthe entire area of the map MP1 shown in FIG. 6. For example, in themodification of the second example of the radio wave environmentanalysis, it is assumed that the transmission point C0 is arranged inthe first block area DSTc1, and radio waves of predetermined strength(for example, 0 dBm) are transmitted, and radio wave environment isanalyzed for the first block area DSTc1. Further, it is assumed that avirtual secondary transmission point (that is, a secondary wirelesstransmitter) that transmits radio waves having the same strength as thepredetermined strength is arranged at positions of positions C1, C2, C3,. . . centering on a position of the transmission point C0 of the firstblock area DSTc1 and existing on an arc at equal intervals for eachdistance r2, and radio wave environment is individually analyzed for acircular block area centering on a position of each secondarytransmission point and having a radius r1. Lastly, in consideration ofthe lower limit of the reception quality of the radio wave environmentand the analysis result data 7 c in the first block area DSTc1, thestrength of the radio waves transmitted by the secondary wirelesstransmitter arranged at each of the secondary transmission points iscorrected, and thus the radio wave environment at the point within theentire area is analyzed (with reference to FIG. 7).

FIG. 7 is a flowchart illustrating a modification of the second exampleof the operation procedure of the radio wave environment analysis at thepoint in the model area shown in FIG. 2. The operation procedure shownin FIG. 7 is performed by, for example, the processor 1 of the radiowave environment display device 100. In the description of the operationprocedure shown in FIG. 7, the same steps as those in the operationprocedure shown in FIG. 5 are donated the same step numbers, thedescription thereof will be simplified or omitted, and differentcontents will be described. In the modification of the second example ofthe analysis, in order to speed up the analysis of the radio waveenvironment display device 100, the analysis is performed for aplurality of circular block areas each having a circular first blockarea DSTc1 centering on the transmission point C0 located at a positionin the map MP1 (area) shown in FIG. 6 and having a plurality ofpositions on the arc of the first block area DSTc1 as secondarytransmission points, and when the analysis result of each block area isused to generate an analysis result in the entire area, the analysisresult of each block area is corrected.

In FIG. 7, various parameters are initialized on the radio waveenvironment display device 100 by a user operation (S11 a).Specifically, as the various parameters, the radio wave environmentdisplay device 100 sets the circular first block area DSTc1 having aradius r1 including the transmission point C0 in which the wirelesstransmitter (not shown) is assumed to be arranged in the map MP1 (area),so as to reduce the number of scattering bodies arranged at each pointof the map MP1 (area) to be equal to or less than a predetermined value.Further, an interval (distance r2) of the secondary transmission pointsarranged on the arc of the first block area DSTc1 is set.

The radio wave environment display device 100 targets the first blockarea DSTc1 (with reference to FIG. 6) set in step S11 a, and use theanalysis basic data 7 b to analyze the radio wave environment at eachpoint in which the scattering body arranged in the first block areaDSTc1 is assumed to be used (S12). That is, the radio wave environmentdisplay device 100 calculates, for each point in the first block areaDSTc1, reception quality (for example, reception power and arrivaldirection) of radio waves from the wireless transmitter (not shown)arranged at the transmission point C0 located on the map MP1 based onthe analysis basic data 7 b, and stores calculation results of thereception power and the arrival direction at each point into the HDD 7as the analysis result data 7 c.

The radio wave environment display device 100 performs a setting ofarranging new transmission points (secondary transmission points) at aplurality of positions (for example, positions C1, C2, C3, . . . ) onthe arc of the circular first block area DSTc1 by using a set value ofthe distance r2 set in step S11 a (S13 a). The radio wave environmentdisplay device 100 targets a circular area (an example of a block area)centering on each of the plurality of secondary transmission points setin step S13 a and having a radius r1, and uses the analysis basic data 7b to analyze the radio wave environment at a point in each area in whicha case where radio waves of predetermined strength is transmitted fromthe secondary transmission points (for example, positions C1, C2, C3, .. . ) is assumed (S13 b). The predetermined strength is, for example,the same strength as the strength (0 dBm) of the radio wave transmittedfrom the transmission point C0. Further, the radio wave environmentdisplay device 100 determines whether or not the similar radio waveenvironment analysis is performed for the block areas provided in theentire area of the map MP1 (specifically, all the block areas includingthe first block area DSTc1) (S14). The radio wave environment displaydevice 100 repeats the processing of steps S13 a and S13 b until thesimilar radio wave environment analysis is performed for the block areas(with reference to the above) provided in the entire area of the map MP1(S14, NO).

On the other hand, if it is determined that the similar radio waveenvironment analysis is performed for the block areas (with reference tothe above) provided in the entire area of the map MP1 (S14, YES), theradio wave environment display device 100 synthesizes the analysisresult data 7 c of the analyses for the respective block areas togenerate the analysis result data 7 c for the entire area in the map MP1(S15).

After step S15, the radio wave environment display device 100 correctsthe analysis result data 7 c of the analyses for the respective blockareas based on the analysis result data 7 c (an analysis result)corresponding to the first block area DSTc1 (S16). Here, correction ofthe analysis result data 7 c in a block area overlapping the first blockarea DSTc1 and each of other block areas adjacent to the block area issimilar to the correction of the second example of the analysis, andtherefore detailed description thereof will be omitted. However, unlikethe second example of the analysis, there is an overlap range betweenblock areas in the modification of the second example of the analysis,so that the analysis result data 7 c in the overlap range is correctedafter the analysis result data 7 c in an upper-level block area (inother words, a block area closer to the transmission point C0) ispreferentially adopted.

Since the processing of the radio wave environment display device 100after step S16 is the same as the processing shown in FIG. 5, thesubsequent description will be omitted.

As described above, the radio wave environment display device 100according to Embodiment 1 analyzes a radio wave environmentcorresponding to transmission of radio waves of predetermined strength(for example, 0 dBm) from a wireless transmitter (not shown) arranged inan area (for example, transmission point C0) of the map MP1. The radiowave environment display device 100 divides an area into a plurality ofblock areas, analyzes, in the processor 1, a radio wave environment byusing a scattering body located in the first block area DSTc1 in whichthe wireless transmitter is arranged, and stores, into the HDD 7 (anexample of a memory), the analysis result of the radio wave environmentat each point of the first block area DST1 based on the analysis. Theradio wave environment display device 100 virtually arranges a secondaryradio transmitter that transmits radio waves of predetermined strength(for example, 0 dBm) at a position (for example, positions C1, C2, C3, .. . on the arc of the first block area DSTc1) where block areasincluding the first block area DSTc1 overlap, and analyzes the radiowave environment corresponding to transmission of the radio waves fromeach secondary wireless transmitter for each block area other than thefirst block area DSTc1. Based on the analysis result of the radio waveenvironment in the first block area DSTc1, the radio wave environmentdisplay device 100 corrects the analysis of the radio wave environmentcorresponding to transmission of the radio waves from each secondarywireless transmitter which is performed for each block area other thanthe first block area DSTc1.

Therefore, a wide area such as outdoors (for example, an area of 25 km²shown in the map MP1) can be divided into a plurality of block areas andthe radio wave environment can be efficiently analyzed for each blockarea, so that the radio wave environment display device 100 canvisualize the radio wave environment at a higher speed. In addition,since the reliability of the analysis result based on the analysis(simulation) for each block area can be improved by finely dividing andanalyzing the block area to be analyzed, the radio wave environmentdisplay device 100 can accurately guarantee the generation accuracy ofthe analysis result data for the entire area after the correction.Therefore, the radio wave environment display device 100 can perform theanalysis at a speed higher than an analysis of the radio waveenvironment at each point for all the scattering bodies actuallyarranged on the map MP1.

For example, in obtaining of the analysis results of the radio waveenvironment over the entire area, there is a need that the observationpoints are arranged at a plurality of points desired to be observed by auser, and the radio wave environment at points other than thoseobservation points are desired to be roughly grasped through analysis(that is, simulation). In this case, since each of the plurality ofblock areas including the first block area DSTc1 is analyzed at a higherspeed and the synthesized analysis result for each block area is alsocorrected, the analysis result data 7 c with high accuracy can also beacquired, so that the radio wave environment display device 100 can alsogenerate the analysis result data 7 c of the radio wave environment thataccurately satisfies the need of the user. In other words, the radiowave environment display device 100 can acquire the analysis result data7 c with high accuracy while performing the analysis at a higher speedeven if there are interactions such as reflection, transmission, anddiffraction of radio waves that exceed a predetermined number of times(for example, 4 to 5 times), which is pointed out as a limit when theray tracing method is used in a wide area such as outdoors.

The radio wave environment display device 100 may omit the calculationbased on a value of the electric field strength in the analyses of StepS2 and Step S3 of the first example of the analysis and the analyses ofStep S12 and Step S13 of the second example of the analysis and in otheranalyses. Specifically, when a calculated electric field strengthexceeds the lower limit value (for example, −100 dBm) (that is, equal toor lower than the lower limit value) specified during the analysis, theradio wave environment display device 100 may omit the analysis of thearea. For example, it is sufficient to perform an analysis in a range ofabout 100 m during analysis of an area of 5 km square if the radio waveis 2 GHz, and the lower limit value is determined in advance before theanalysis, so that the radio wave environment display device 100 omitsthe analysis of the area when the calculated electric field strength isequal to or lower than the lower limit value. Therefore, the radio waveenvironment display device 100 does not calculate an unnecessary route,and the analysis can be performed at a higher speed.

The radio wave environment display device 100 may individually performthe same analysis (with reference to FIG. 3) as the analysis describedin the first example of the analysis in the analysis for each block areain steps S12 and S13 b. Accordingly, the radio wave environment displaydevice 100 can perform analysis in consideration of the magnitude of thevolume of the scattering body arranged for each block area, andtherefore, the analysis can be performed at a higher speed.

Third Example of Analysis

FIG. 8 is a diagram illustrating an example of a model area simulated bythe radio wave environment display device 100 according to Embodiment 1.As shown in FIG. 8, a third example of the model area simulated by theradio wave environment display device 100 according to Embodiment 1(that is, a third example of the radio wave environment analysis at thepoint in an area) is similarly a wide area, for example, outdoors or thelike. As an example of the model area, FIG. 8 shows the map MP1 (withreference to FIG. 2) of an area having an area of 5 km*5 km (*: anoperator indicating multiplication)=25 km².

In the third example of the radio wave environment analysis, the radiowave environment display device 100 sets a location of the wirelesstransmitter at a position of the area of the map MP1 (that is, atransmission point D0). The radio wave environment display device 100calculates a radio wave attenuation amount within a range of apredetermined angle (for example, 1°) from the transmission point D0, ata position (that is, an observation point) away from the transmissionpoint D0 by a distance designated by a user operation in a case whereuniform rays (that is, radio waves of predetermined strength) in alldirections of 360 degrees are transmitted from the transmission pointD0. The predetermined strength is, for example, “0 dBm”.

FIG. 9 is a diagram schematically illustrating an example of calculationof a radio wave attenuation amount of radio waves WV1 at points (forexample, positions RR1, RR2) located within a range of 1° in which radiowaves are transmitted from the transmission point D0. As shown in FIG.9, the transmission point D0 corresponds to the transmission point D0shown in FIG. 8. When the radio waves WV1 of predetermined strength (forexample, 0 dBm) are transmitted from the wireless transmitter arrangedat the transmission point D0 within a range of 1° centering on thetransmission point D0 (for example, within a fan-shaped range defined bythe transmission point D0 and the positions RR1, RR2 on an arc in thecase of centering on the transmission point D0), respective radio waveattenuation amounts at the positions RR1, RR2 are calculated by theradio wave environment display device 100.

Here, a metal body MT1 and a wood WD2 are arranged on a virtual straightline from the transmission point D0 toward the position RR1. Since themetal body reflects the radio waves without transmitting the radiowaves, the radio waves WV1 do not reach the position RR1 from thetransmission point D0, and calculation of the radio wave attenuationamount at the position RR1 is omitted in the radio wave environmentdisplay device 100.

Meanwhile, on a virtual straight line from the transmission point D0 tothe position RR2, the metal body is not arranged, and two concretestructures CC1, CC2 and a wood WD1 are arranged. Therefore, when theradio waves WV1 reach the position RR2 from the transmission point D0,the radio wave environment display device 100 calculates the radio waveattenuation amount at the position RR2 as follows.

Specifically, the radio wave environment display device 100 calculatesthe radio wave attenuation amount within the range of 1° shown in FIG. 9from the transmission point D0 (within the fan-shaped range defined bythe transmission point D0 and the positions RR1, RR2 on an arc in thecase of centering on the transmission point D0) as a total value of(Element 1) an attenuation amount depending on a distance (D0,RR2(=RR1))+(Element 2) a material constant (for example, an attenuationamount) of the concrete structure CC1+(Element 3) a material constant(for example, an attenuation amount) of the concrete structureCC2+(Element 4) a material constant (for example, an attenuation amount)of the wood WD1. The distance (D0, RR2) indicates a minimum value of adistance between the transmission point D0 and the position RR2 (thatis, a distance between the transmission point D0 and the position RR2arranged on a straight line).

The (Element 1) can be calculated by a known radio wave attenuationamount formula based on the distance, and is stored in advance in theprogram 7 a of the HDD 7. For the (Element 2), (Element 3), and (Element4), data (an example of the scattering body data) of material constants(for example, default values) corresponding to the concrete structuresand the wood serving as examples of the scattering bodies may beincluded in the analysis basic data 7 b in advance, and the materialconstant data may be received in advance from an external device (notshown) communicatively connected to the radio wave environment displaydevice 100, stored in the HDD 7, and read out whenever necessary. Basedon data of the map MP1 included in the analysis basic data 7 b, theradio wave environment display device 100 can recognize what kind ofscattering body exists (is arranged) on routes from the transmissionpoint D0 to the positions RR1, RR2 designated by the user operation.

FIG. 10 is a flowchart illustrating a third example of the operationprocedure of the radio wave environment analysis at the point in themodel area shown in FIG. 2. The operation procedure shown in FIG. 10 isexecuted by, for example, the processor 1 of the radio wave environmentdisplay device 100. In the third example of the analysis, in order tospeed up the analysis of the radio wave environment display device 100,when a position of the observation point desired to be observed by theuser from the transmission point D0 is designated, the radio waveattenuation amount is calculated according to a distance from thetransmission point D0 to the observation point located within a range ofa predetermined angle and a type of the scattering body.

In FIG. 10, various parameters are initialized on the radio waveenvironment display device 100 by a user operation (S21). Specifically,as the various parameters, the radio wave environment display device 100sets a position of the transmission point D0 and a distance of theobservation point desired to be observed by the user from thetransmission point D0, and then sets a unit angle (an example of apredetermined angle, for example, 1°) that determines an area for whichthe radio wave attenuation amount is calculated.

The radio wave environment display device 100 simulates (simulates)transmission (radiation) of the radio waves WV1 having uniform strength(for example, 0 dBm) from the transmission point D0 to 360° (that is, inall directions) (S22). The radio wave environment display device 100counts the number of scattering bodies through which the radio waves WV1pass in the area based on the data of the map MP1 of such as outdoors ordata of the layout of such as indoors included in the analysis basicdata 7 b (S23).

The radio wave environment display device 100 determines transmission ornon-transmission of the radio waves WV1 for each scattering body countedin step S23 (S24). For example, the radio wave environment displaydevice 100 determines that the scattering body is non-transmissive whenthe scattering body is a metal body and determines that the scatteringbody is transmissive when the scattering body is not a metal body.

The radio wave environment display device 100 calculates the radio waveattenuation amount for each area by using material constants (forexample, the attenuation amount of (Element 2) to (Element 4))corresponding to the scattering bodies which are determined to benon-transmissive in step S24 using the analysis basic data 7 b, and theattenuation amount depending on the distance from the transmission pointD0 (for example, with reference to (Element 1)) (S25). In step S25, theradio wave environment display device 100 performs the processing ofsteps S23 to S25 while scanning every unit angle (for example, 1°) ofall directions of 360°.

After step S25, the radio wave environment display device 100 terminatesthe radio wave environment analysis at the point in the area of the mapMP1. Further, the radio wave environment display device 100 displays, onthe display 6, an analysis result (not shown) of the radio waveenvironment analysis at the point in the area of the map MP1 (S26).

As described above, the radio wave environment display device 100according to Embodiment 1 analyzes a radio wave environmentcorresponding to transmission of radio waves of predetermined strength,(for example, 0 dBm) from a wireless transmitter arranged at thetransmission point D0 in the area. The radio wave environment displaydevice 100 counts, in the processor 1, the number of one or morescattering bodies located within a range of a predetermined angle (forexample, 1°) from the arrangement position of the wireless transmitter(that is, the transmission point D0). The radio wave environment displaydevice 100 reads out, from the HDD 7 (an example of the memory), thescattering body data in which the type of each of the scattering bodiesof the counted number and the radio wave attenuation amountcorresponding to the type are associated with each other. When the radiowaves of predetermined strength are transmitted from the wirelesstransmitter in all directions, the radio wave environment display device100 calculates a radio wave attenuation amount at a position which islocated within the range of a predetermined angle and is away from thearrangement position by a designated distance, based on the count resultof the scattering bodies positioned within the range of a predeterminedangle and the scattering body data.

Therefore, the radio wave environment display device 100 can analyze theradio wave environment, for a wide area such as outdoors (for example,an area of 25 km² or more shown in the map MP1) in a position of eachpredetermined angle that is away from the transmission point D0 by adistance designated by the user, easily and at a higher speed, so thatthe radio wave environment display device 100 can assist in visualizingthe radio wave environment at a higher speed. For example, even in acase where the wireless transmitter located at the transmission point D0moves in a moving body (for example, a vehicle), or the like, the radiowave environment display device 100 can similarly analyze the radio waveenvironment simply and at a higher speed according to the third exampleof the analysis, so that user convenience can be improved.

Background of Contents of Embodiment 2

In the related art including IMAI, it has been disclosed to display theanalysis result of the radio wave environment for the area (that is, thesimulation result of the radio wave environment at a point in the area).However, the analysis result to be displayed does not always match auser intention of confirming the analysis result, it is difficult toimprove the user convenience in a point of satisfying the need of theuser to check in more detail in a specific region or flow line.

Embodiment 2

Therefore, in the following Embodiment 2, an example of a radio waveenvironment display device and a radio wave environment display methodthat assist in efficiently extracting and visualizing an analysis resulton a region or a flow line desired to be observed by a user when ananalysis of a radio wave environment performed for a wide area isdisplayed will be described. Since a configuration of the radio waveenvironment display device according to Embodiment 2 is the same as thatof the radio wave environment display device 100 according to Embodiment1, the same components will be denoted by the same reference numerals,the description thereof will be simplified or omitted, and differentcontents will be described.

FIG. 11 is a diagram illustrating an example of a visualization resultof a radio wave environment targeted in a shopping mall SML1 in which aplurality of access points AP1, AP2, AP3, AP4, AP5 are arranged and anexample of an extraction range AREA1 designated by a user in the radiowave environment display device 100 according to Embodiment 2. FIG. 12is a diagram illustrating an example of a visualization result of aradio wave environment targeted in the shopping mall SML1 in which theplurality of access points AP1, AP2, AP3, AP4, AP5 are arranged and anexample of a flow line PTH1 designated by a user in the radio waveenvironment display device 100 according to Embodiment 2.

In Embodiment 2, the radio wave environment display device 100 analyzesa radio wave environment according to, for example, the method describedin Embodiment 1 by setting a wide area targeted for the radio waveenvironment analysis as the shopping mall SML1, and displays theanalysis result of the analysis on the display 6. The displayed analysisresult is shown in FIG. 11 or 12.

As shown in FIG. 11, when the user performs an operation of selecting anextraction range ARE1 and a time zone with a mouse 5 in the shoppingmall SML1, the radio wave environment display device 100 generates andextracts an analysis result (for example, an example of an electricfield strength distribution or a cumulative probability distribution,and partial radio wave environment distribution data) at a point withinthe selected extraction range ARE1 in the selected time zone in responseto the operation, and displays the analysis result on the display 6.Even if the user does not select the extraction range ARE1 using themouse 5, the radio wave environment display device 100 may sequentiallyselect a random extraction range within the shopping mall SML1 everypredetermined time according to a selection condition of selecting apredetermined extraction range, generate and extract an analysis result(for example, an example of an electric field strength distribution or acumulative probability distribution, and partial radio wave environmentdistribution data) at a point within the selected extraction range, anddisplay the analysis result on the display 6.

As shown in FIG. 12, when the user performs an operation of selectingthe flow line PTH1 from a start point G1 to an end point G2 and a timezone with the mouse 5 in the shopping mall SML1, the radio waveenvironment display device 100 generates and extracts an analysis result(for example, an example of an electric field strength distribution or acumulative probability distribution, and partial radio wave environmentdistribution data) at a point within the selected flow line PTH1 in theselected time zone in response to the operation, and displays theanalysis result on the display 6. Even if the user does not select theflow line PTH1 using the mouse 5, the radio wave environment displaydevice 100 may sequentially select a random flow line within theshopping mall SML1 every predetermined time according to a selectioncondition of selecting a predetermined flow line, generate and extractan analysis result (for example, an example of an electric fieldstrength distribution or a cumulative probability distribution, andpartial radio wave environment distribution data) at a point on theselected flow line, and display the analysis result on the display 6.

In this way, the radio wave environment display device 100 according toEmbodiment 2 acquires, in the processor 1, radio wave environment dataobtained by associating, with position information within an area (forexample, the shopping mall SML1) having a plurality of observationpoints, an analysis result based on an analysis of the radio waveenvironment corresponding to transmission of radio waves from at leastone wireless transmitter (for example, the access points AP1, AP2, AP3,AP4, AP5) positioned within the area; and stores the radio waveenvironment data into HDD7 (an example of a memory). The radio waveenvironment display device 100 selects a region that is a part of thearea, extracts partial radio wave environment data corresponding to theselected part, and outputs predetermined radio wave environmentdistribution data based on the extracted partial radio wave environmentdata on the display 6.

Therefore, when the analysis of the radio wave environment performed forthe wide area (for example, the shopping mall SML1) is displayed, theradio wave environment display device 100 can assist in efficientlyextracting and visualizing an analysis result of a part of the shoppingmall SML1 (for example, a region or a flow line showing an extractionrange) desired to be observed by the user and selected by the useroperation or the random selection. Therefore, since the radio waveenvironment display device 100 can visually present the analysis resultof the radio environment in a part of the shopping mall SML1 to theuser, it is possible to promote the user to determine, for example,whether or not there is a difference with a radio wave environmentassumed by the user, and to improve the user convenience.

The radio wave environment display device 100 includes the mouse 5 orthe keyboard 4 (an example of an operation input unit) through which auser operation is input, and extracts the partial radio wave environmentdata corresponding to the designated part in response to the designationoperation of designating a part of the area by the user. As a result,the radio wave environment display device 100 can visually display theanalysis result that satisfies the need for the user to check in moredetail in a specific region or flow line of the shopping mall SML1, andthus the user convenience can be improved.

A part of the area is a region that is a part of the area (for example,the extraction range ARE1) including the point where the wirelesstransmitters (for example, the access points AP3, AP4) are arranged.Therefore, the radio wave environment display device 100 can visuallypresent to the user the arrangement positions of the access points AP3,AP4 in the extraction range ARE1 including the access points AP3, AP4and the analysis result of the radio wave environment within theextraction range ARE1. Therefore, the user can easily confirm, forexample, whether or not the arrangement positions of the access pointsAP3, AP4 are appropriate arrangement positions in the shopping mallSML1.

Further, a part of the area is a flow line of one or more personspassing through a point where a wireless transmitter (for example, theaccess points AP1, AP2, AP3, AP5) is arranged or a position near thepoint. Therefore, the radio wave environment display device 100 canvisually present a relationship between a layout of stores or the likeon the flow line through which shoppers pass in the shopping mall SML1and the arrangement positions of the access points AP1, AP2, AP3, AP5 inthe flow line PTH1 passing through the points where the access pointsAP1, AP2, AP3, AP5 are arranged or positions near the points to the userbased on the analysis result of the radio wave environment. Therefore,the user can easily confirm, for example, whether or not the arrangementpositions of the access points AP1, AP2, AP3, AP5 are appropriatearrangement positions in the relationship with the layout of the storesor the like in the shopping mall SML1.

FIG. 13 is a diagram illustrating respective coverage areas of theplurality of access points AP1, AP2, AP3, AP4, AP5 arranged in theshopping mall SML1 shown in FIG. 11 and an example of a flow line PTH2designated by a user. FIG. 14 is a graph illustrating a transitionexample of the number of terminal connections or throughput at each ofthe access points on the flow line PTH2 shown in FIG. 13. The shoppingmall SML1 shown in FIG. 13 is the same as the shopping mall SML1 shownin FIG. 11 or FIG. 12.

When the user performs an operation of selecting the flow line PTH2 fromthe start point G3 to the end point G4 and a time zone desired to beobserved using the mouse 5, the radio wave environment display device100 extracts an analysis result (for example, an example of partialradio wave environment distribution data) at a point within the selectedflow line PTH2 in the selected time zone in response to the operation.The radio wave environment display device 100 uses the extractedanalysis result to analyze how many wireless terminals (for example,smart phones owned by shoppers) are connected to the access points onthe flow line PTH2 and which access point are connected in the selectedtime zone, or analyze throughput that can be provided to each terminalbased on the connection with the access point. The radio waveenvironment display device 100 displays a graph of the analysis result(see FIG. 14) on the display 6.

In FIG. 14, a transition of the number of terminal connections orthroughput at each of the access points AP1, AP2, AP3 arranged on theflow line PTH2 or a vicinity position thereof in the time zonedesignated by the user operation is shown in a bar graph.

FIG. 15 is a diagram illustrating respective coverage areas of theplurality of access points arranged in the shopping mall shown in FIG.11 and an example of an extraction range designated by a user. FIG. 16is a graph illustrating a transition example of the number of terminalconnections or throughput at each of the access points in the extractionrange shown in FIG. 15. The shopping mall SML1 shown in FIG. 15 is thesame as the shopping mall SML1 shown in FIG. 11 or FIG. 12.

When the user performs an operation of selecting the extraction rangeARE1 and a time zone desired to be observed using the mouse 5, the radiowave environment display device 100 extracts an analysis result (forexample, an example of partial radio wave environment distribution data)at a point within the selected extraction range ARE1 in the selectedtime zone in response to the operation. The radio wave environmentdisplay device 100 uses the extracted analysis result to analyze howmany wireless terminals (for example, smart phones owned by shoppers)are connected to the access points at the point within the extractionrange ARE1 and which access point are connected in the selected timezone, or analyze throughput that can be provided to each terminal basedon the connection with the access point. The radio wave environmentdisplay device 100 displays a graph of the analysis result (see FIG. 16)on the display 6.

In FIG. 16, a transition of the number of terminal connections orthroughput at each of the access points AP3, AP4 arranged in theextraction range ARE1 in the time zone designated by the user operationis shown in a bar graph.

Thus, the radio wave environment display device 100 according toEmbodiment 2 analyzes, based on the analysis result (an example ofpartial radio wave environment data) extracted in the predeterminedperiod (for example, the time zone selected by the user), dataindicating a status of a wireless terminal that can be connected to awireless transmitter (access point) corresponding to the part in thepredetermined period, and outputs the analysis result to the display 6.Accordingly, the radio wave environment display device 100 can associatethe arrangement positions of one or more access points arranged in ornear the flow line PTH2 or the extraction range ARE1 in the time zoneselected by the user with the analysis result of the radio waveenvironment (for example, the number of terminal connections or thethroughput), and visually present the arrangement positions and theanalysis result to the user. Therefore, the user can easily confirm, forexample, whether the arrangement position of each access point arrangedin the shopping mall SML1 is a position where a good communicationenvironment for wireless terminals of such as shoppers in the shoppingmall SML1 can be provided.

Modification of Embodiment 2

In a display example of the analysis result of the radio waveenvironment described in Embodiment 2, for example, as shown in FIG. 11or FIG. 12, the strength of the two-dimensional reception quality (forexample, the reception power) in a plan view or perspective view (notshown) is classified and displayed by color or the like. However, in thedisplay example, in a case where the heights of the positions of theobservation points are different, it is difficult to display theanalysis results by distinguishing the positions of different heights.In actual measurement of the radio wave environment, a case wherepositions of the observation points are different for each height isalso assumed, so that in the display example of Embodiment 2, it is notpossible to visually present the analysis result at differentobservation points for each height.

In a modification of Embodiment 2, the radio wave environment displaydevice 100 does not show the analysis result at the observation point intwo-dimensional color classification in either plan view or perspectiveview (for example, with reference to a left side in FIG. 18), but showsthe analysis results at the same observation point as athree-dimensional index such as a sphere or polyhedron (for example,with reference to a right side in FIG. 18). FIG. 18 is a diagramillustrating an example of an outline of an operation of visualizing theradio wave environment for each height.

As shown on the left side of FIG. 18, a region RG1 as an example of thesub-region is a region of a rectangle or a square having a distanced1*distance d2 (*: an operator indicating multiplication), and is aregion having a constant area including an observation point (forexample, a center position of the region RG1). The analysis result ofthe radio wave environment in the region RG1 (for example, the strengthof the reception power) is an average value of the strength of thereception power at respective points in the region RG1, and, forexample, is shown by a two-dimensional pattern PT1 filled with red.However, when the analysis result is shown by the pattern PT1 on thedisplay 6, as described above, in a case where the strength of thereception power differs for each height even at the same observationpoint, the different strength of the reception power is not visuallyreflected and displayed.

The radio wave environment display device 100 according to themodification of Embodiment 2 displays the average value of the strengthof the reception power in the region RG1 having the same area on thedisplay 6 by using, for example, a three-dimensional sphere MG1 paintedin red, as shown on the right side of FIG. 18. This sphere MG1 has anoccupation rate of a portion smaller than the area of the region RG1.The radio wave environment display device 100 omits displaying thestrength of the reception power in a display part other than the displaypart of the sphere MG1 in the region RG1 (in other words, displayed in atransparent color).

FIG. 17 is a diagram illustrating an example of a visualization resultof a radio wave environment shown for each height from a floor surfacein the radio wave environment display device 100 according to themodification of Embodiment 2. A floor surface H1PL is, for example, afloor surface (ground) of the area that is a target of the radio waveenvironment analysis. Virtual planes H2PL, H3PL, . . . shown by dottedlines in FIG. 17 are two-dimensional virtual planes indicating positionsabove the floor surface H1PL by a predetermined distance (in otherwords, positions at different heights from the floor surface). As shownin FIG. 17, the radio wave environment display device 100 according tothe modification of Embodiment 2 can display not only the analysisresult of the radio wave environment at a height of the floor surfaceH1PL on the display 6, but also the analysis results of the radio waveenvironment at heights of the virtual planes H2PL, H3PL, . . . on thedisplay 6 by arranging and overlapping the analysis results on a sphere(with reference to the sphere MG1 shown in FIG. 17).

For example, in the same region RG1 as the region RG1 shown in FIG. 18,the strength of the radio wave reception power on the floor surfaceH1PL, the strength of the radio wave reception power on the virtualplane H2PL, and the strength of the radio wave reception power on thevirtual plane H3PL are respectively shown by spheres MG1, MG2, MG3 ofdifferent colors. That is, the strength of the radio wave receptionpower on the floor surface H1PL, the strength of the radio wavereception power on the virtual plane H2PL, and the strength of the radiowave reception power on the virtual plane H3PL are different, so thatthe radio wave environment display device 100 can visually present theanalysis results of the radio wave environment, which are different foreach height.

As described above, the radio wave environment display device 100according to the modification of the Embodiment 2 divides, for example,partial radio wave environment data in an extraction range or a flowline selected by a user operation into partial radio wave environmentdata for each of a plurality of sub regions (for example, the regionRG1) obtained by dividing a part into a plurality of regions each havinga predetermined area, and displays the partial radio wave environmentdata corresponding to the sub-region obtained by dividing on a sphereMG1 or the like having an area smaller than the predetermined area (withreference to FIG. 17). Whether the extraction range is selected or theflow line is selected, the predetermined area is a minute area thatconstitutes the area of the extraction range or the flow line, and thesame applies hereinafter. As a result, the radio wave environmentdisplay device 100 can visually present the analysis result of the radiowave environment different for each height, and even when the analysisresult of the radio wave environment at a point in the area for eachheight is displayed in an overlapping manner, deterioration of thevisibility of the analysis result can also be effectively prevented.

Further, the radio wave environment display device 100 according to themodification of the Embodiment 2 divides, for example, partial radiowave environment data in an extraction range or a flow line selected bya user operation into partial radio wave environment data for each of aplurality of sub regions (for example, the region RG1) obtained bydividing a part into a plurality of regions each having a predeterminedarea, and displays the partial radio wave environment data correspondingto the sub-region obtained by dividing on a cone (not shown) or the likehaving an area smaller than the predetermined area. In this way, theradio wave environment display device 100 can visually present not onlythe strength of the reception power as the analysis result of the radiowave environment different for each height, but also an arrivaldirection of the radio waves in a direction from a pointed shape of suchas a cone toward a bottom surface of the cone. Further, the radio waveenvironment display device 100 can prevent deterioration of thevisibility of the analysis result even when the analysis result of theradio wave environment at a point in the area for each height isdisplayed in an overlapping manner.

Although various embodiments have been described above with reference tothe drawings, it is needless to say that the present disclosure is notlimited to such examples. It will be apparent to those skilled in theart that various alterations, modifications, substitutions, additions,deletions, and equivalents can be conceived within the scope of theclaims, and it should be understood that they also belong to thetechnical scope of the present disclosure. Each component in the variousembodiments described above may be combined freely in the range withoutdeviating from the spirit of the invention.

The present application is based on a Japanese Patent Application(Patent Application No. 2018-044718) filed on Mar. 12, 2018, thecontents of which are incorporated herein by reference.

The present disclosure is useful as a radio wave environment displaydevice and a radio wave environment display method that assist inefficiently extracting and visualizing an analysis result on a region ora flow line desired to be observed by a user when an analysis of a radiowave environment performed for a wide area is displayed.

1. A radio wave environment display device comprising: a processorconfigured to acquire radio wave environment data obtained byassociating, with position information within an area comprising aplurality of observation points, an analysis result based on an analysisof a radio wave environment corresponding to a radio wave transmittedfrom at least one wireless transmitter arranged within the area; and amemory configured to store the radio wave environment data, wherein theprocessor is configured to: select a region that is a part of the area;extract partial radio wave environment data corresponding to theselected part; and output predetermined radio wave environmentdistribution data based on the extracted partial radio wave environmentdata on a display device.
 2. The radio wave environment display deviceaccording to claim 1 further comprising: an operation input unitconfigured to receive an operation of a user, wherein in response to adesignation operation of the user designating a part of the area, theprocessor is configured to extract partial radio wave environment datacorresponding to the designated part.
 3. The radio wave environmentdisplay device according to claim 1, wherein the part of the areacomprises a point where the wireless transmitter is arranged.
 4. Theradio wave environment display device according to claim 1, wherein thepart of the area comprises a flow line of one or more persons passingthrough a point where the wireless transmitter is arranged or a positionnear the point.
 5. The radio wave environment display device accordingto claim 3 wherein the processor is configured to: analyze, based on thepartial radio wave environment data extracted in a predetermined period,data which indicates a status of a wireless terminal connectable to thewireless transmitter and corresponds to the part in the predeterminedperiod; and output an analysis result to the display device.
 6. Theradio wave environment display device according to claim 1, wherein theprocessor is configured to: divide the partial radio wave environmentdata into partial radio wave environment data for each of a plurality ofsub-regions obtained by dividing the part such that each of theplurality of sub-regions has a predetermined area; and display thepartial radio wave environment data corresponding to the sub-region witha sphere having an area smaller than the predetermined area.
 7. Theradio wave environment display device according to claim 1, wherein theprocessor is configured to: divide the partial radio wave environmentdata into partial radio wave environment data for each of a plurality ofsub-regions obtained by dividing the part such that each of theplurality of sub-regions has a predetermined area; and display thepartial radio wave environment data corresponding to the sub-region witha cone having an area smaller than the predetermined area.
 8. A radiowave environment display method to be performed in a radio waveenvironment display device, the radio wave environment display methodcomprising: acquiring radio wave environment data obtained byassociating, with position information within an area comprising aplurality of observation points, an analysis result based on an analysisof a radio wave environment corresponding to a radio wave transmittedfrom at least one wireless transmitter arranged within the area; storingthe radio wave environment data into a memory; selecting a region thatis a part of the area, and extracting partial radio wave environmentdata corresponding to the selected part; and outputting predeterminedradio wave environment distribution data based on the extracted partialradio wave environment data on a display device.